Conventional pneumatic tires have a circumferential reinforcing layer in a belt layer in order to suppress the radial growth of tires. The technology disclosed in Japanese Unexamined Patent Application Publication No. 2010-208505A is a conventional pneumatic tire that is configured in this manner.
When remaining grooves of a tread portion of heavy duty radial tires mounted on trucks, buses, and the like reach the end of their service life, a tread surface is removed by buffing, and new rubber material is applied to the remaining tire main body (tire casing), which is then reused as a renewed tire.
In tires having a circumferential reinforcing layer in a belt layer, shoulder wear (in particular, step wear) tends to easily occur. If the shoulder wear is large, it is not possible to remove the shoulder wear by buffing, and it is not possible to renew the tire. This is because if a large amount of the shoulder wear is removed by buffing, end portions of the belt layer are exposed.
On the other hand, frequently, it is determined whether or not a tire can be renewed after buffing. In this case, the buffing process may be wasteful, which is detrimental for the user (mainly, the tire dealer that carries out the buffing), so this is not desirable.